Artificial Sweeteners Might Get in the Way of Weight Loss
A new study has shot to hell all our comfort and smugness in consuming ‘diet’ and ‘lite’ foods that use artificial sweetners instead of sugar. Published in the journal Cell Metabolism, researchers have found that artificial sweeteners, when combined with a low-carb diet (like, for example, the Atkins diet) significantly increases the quantity of calories consumed.
The study, led by the University of Sydney’s Charles Perkins Centre and School of Life and Environmental Sciences, offered fruit flies diets with varying amounts of carbohydrate and sweeteners, and tracked their resulting food intake. Flies that consumed artificial sweeteners alongside a low-carb diet showed an immediate increase in food intake. This increase varied according to the dose of sweeteners provided and was not observed in flies consuming unsweetened foods.
This builds on a study released last month, also by the Charles Perkins Centre as well as the Garvin Institute for Medical Research, which found fruit flies with prolonged diets that included sucralose (a common artificial sweetener; you may know it by its commercial name, Splenda) consumed 30% more calories once they switched back to diets containing sucrose (sugar). These findings were replicated in a similar experiment using mice. (Indeed, these findings support a growing body of evidence that artificial sweeteners can mess with the body’s metabolism in a way that promotes weight gain.)
The theory is that artificial sweeteners — maybe especially when combined with a low-carb diet — trick the brain into thinking the body is in a state of starvation, which leads to increased calorie consumption in a fight for survival.
There is, of course, a big difference between fruit flies and mice and humans. But considering that our human brains often actively work against our goals — and how difficult and complex weight loss is — it wouldn’t be a surprise to learn something similar is going on in human brains; the study’s authors are calling for further research.
(It’s important to note here that a different, past study reported that flies’ consumption of artificial sweeteners in the context of a higher-carb diet actually suppressed food intake, which could therefore help reduce calories consumed and promote weight loss; but the results of this study were not reproduceable, and flies that were offered a higher carbohydrate diet and consumed higher doses of artificial sweeteners did not simultaneously reduce their food intake.)
Lead researcher Associate Professor Greg Neely, from the University of Sydney’s Faculty of Science, said the new findings supported the team’s conclusions from last month’s.
“Distorting the perceived energy value of food, by manipulating sweetness through artificial means, has unanticipated consequences in these animal studies,” he said. “Although originally considered benign, a growing body of research including our own makes clear a connection between artificial sweeteners, hunger and food intake.”